[node vulnerability] Nodes that are catching up are vulnerable

[dangershony]

Nodes that are catching up with the longest chain are vulnerable to malicious peers that can during the catch up serve a fake longer chain.

Proposed by @Aprogiena to not sync form inbound connections during that phase.

[dangershony]

The proposed solution is to prevent the puller to download blocks from peers that are inbounds during IBD

[Aprogiena]

Actually, the solution should be not to open the server for inbounds connections before IBD is finished.

[bokobza]

Added: Allow whitelisted nodes as inbound connections.

[noescape00]

Issue's fix description:

In NetworkPeerServer.AcceptClientsAsync

replace comment in red circle with actual implementation

Additionally for investigation:
check how we whitelist peers. Maybe we should keep 2 lists of peers- whitelisted ones and those that come from addNode and connect parameters.

[ferdeen]

check how we whitelist peers. Maybe we should keep 2 lists of peers- whitelisted ones and those that come from addNode and connect parameters.

Went through this with @noescape00 and white listed nodes are stored in ConnectionManagerSettings :

StratisBitcoinFullNode/src/Stratis.Bitcoin/Configuration/Settings/ConnectionManagerSettings.cs

Lines 89 to 90 in f780d8e

	this.Listen.AddRange(config.GetAll("whitebind", this.logger)
	.Select(c => new NodeServerEndpoint(c.ToIPEndPoint(port), true)));

So we don't need to keep two lists, just inject ConnectionManagerSettings and check if the TcpClient is in the list of listeners. If so, then check if its Whitelisted.

[bokobza]

Closed with #1991